Heart Failure USMLE Step 1 Practice Question
A 3-week-old infant presents with tachypnea, poor feeding, and failure to gain weight. Vital signs show heart rate 165 bpm, respiratory rate 58/min, blood pressure 65/40 mmHg, and oxygen saturation 88% on room air. The infant has no cyanosis at rest. Echocardiography reveals a single arterial trunk arising from the heart, supplying systemic, pulmonary, and coronary circulations. Chest X-ray shows pulmonary edema. Which embryologic defect most likely caused this condition?
Answer choices
- AFailure of neural crest migration into the aorticopulmonary septumCorrect answer
- BAbnormal left right dynein function
- CFailure of ductus arteriosus to close
- DFailure of endocardial cushion fusion
- EFailure of septum primum to resorb
- FFailure of the truncus arteriosus to divide into aortic and pulmonary channels during weeks 4-6 of development
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